It might be worth mentioning if you ever come across one of these notes written on sheet music (for the select few here who will even look at sheet music), you play the note that the music implies. That is, for example if it is written Fb, you play E.

Basically, Fb is saying 'play me one semitone below F'. Because flats and sharps are semitones below and above the note.

So E is a semitone below F, and B is a semitone below C.


So after all my flabbergasting, it exists on sheet music, it is rather incorrect, but play the note a semitone above or below.

Meh.